sprof.1, eventfd.2, execve.2, futex.2, getdents.2, mprotect.2, open_by_handle_at.2, recvmmsg.2, sched_setaffinity.2, CPU_SET.3, backtrace.3, bsearch.3, dl_iterate_phdr.3, dlinfo.3, duplocale.3, encrypt.3, envz_add.3, fopencookie.3, getaddrinfo.3, getaddrinfo_a.3, getdate.3, getgrent_r.3, getgrouplist.3, getifaddrs.3, getprotoent_r.3, getservent_r.3, hsearch.3, mallinfo.3, malloc_info.3, mbstowcs.3, mtrace.3, pthread_create.3, pthread_getcpuclockid.3, pthread_setaffinity_np.3, qsort.3, rand.3, strcat.3, strtok.3, tsearch.3, wordexp.3, core.5, aio.7, inotify.7, sock_diag.7, unix.7, user_namespaces.7: Use C99 style to declare loop counter variables

Rather than:

    sometype x;

    for (x = ....; ...)

use

    for (sometype x = ...; ...)

This brings the declaration and use closer together (thus aiding
readability) and also clearly indicates the scope of the loop
counter variable.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man1/sprof.1

@@ -116,35 +116,27 @@ $ \fBcat libdemo.c\fP
 void
 consumeCpu1(int lim)
 {
-    int j;
+    for (int j = 0; j < lim; j++)
-
-    for (j = 0; j < lim; j++)
 	getppid();
 }
 
 void
 x1(void) {
-    int j;
+    for (int j = 0; j < 100; j++)
-
-    for (j = 0; j < 100; j++)
 	consumeCpu1(200000);
 }
 
 void
 consumeCpu2(int lim)
 {
-    int j;
+    for (int j = 0; j < lim; j++)
-
-    for (j = 0; j < lim; j++)
 	getppid();
 }
 
 void
 x2(void)
 {
-    int j;
+    for (int j = 0; j < 1000; j++)
-
-    for (j = 0; j < 1000; j++)
 	consumeCpu2(10000);
 }
 .EE

man2/eventfd.2

@@ -396,7 +396,7 @@ Parent read 28 (0x1c) from efd
 int
 main(int argc, char *argv[])
 {
-    int efd, j;
+    int efd;
     uint64_t u;
     ssize_t s;
 
@@ -411,7 +411,7 @@ main(int argc, char *argv[])
 
     switch (fork()) {
     case 0:
-        for (j = 1; j < argc; j++) {
+        for (int j = 1; j < argc; j++) {
             printf("Child writing %s to efd\en", argv[j]);
             u = strtoull(argv[j], NULL, 0);
                     /* strtoull() allows various bases */

man2/execve.2

@@ -794,9 +794,7 @@ It just echoes its command-line arguments, one per line.
 int
 main(int argc, char *argv[])
 {
-    int j;
+    for (int j = 0; j < argc; j++)
-
-    for (j = 0; j < argc; j++)
         printf("argv[%d]: %s\en", j, argv[j]);
 
     exit(EXIT_SUCCESS);

man2/futex.2

@@ -1828,7 +1828,7 @@ int
 main(int argc, char *argv[])
 {
     pid_t childPid;
-    int j, nloops;
+    int nloops;
 
     setbuf(stdout, NULL);
 
@@ -1858,7 +1858,7 @@ main(int argc, char *argv[])
         errExit("fork");
 
     if (childPid == 0) {        /* Child */
-        for (j = 0; j < nloops; j++) {
+        for (int j = 0; j < nloops; j++) {
             fwait(futex1);
             printf("Child  (%ld) %d\en", (long) getpid(), j);
             fpost(futex2);
@@ -1869,7 +1869,7 @@ main(int argc, char *argv[])
 
     /* Parent falls through to here */
 
-    for (j = 0; j < nloops; j++) {
+    for (int j = 0; j < nloops; j++) {
         fwait(futex2);
         printf("Parent (%ld) %d\en", (long) getpid(), j);
         fpost(futex1);

man2/getdents.2

@@ -280,7 +280,6 @@ main(int argc, char *argv[])
     int fd, nread;
     char buf[BUF_SIZE];
     struct linux_dirent *d;
-    int bpos;
     char d_type;
 
     fd = open(argc > 1 ? argv[1] : ".", O_RDONLY | O_DIRECTORY);
@@ -297,7 +296,7 @@ main(int argc, char *argv[])
 
         printf("\-\-\-\-\-\-\-\-\-\-\-\-\-\-\- nread=%d \-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\en", nread);
         printf("inode#    file type  d_reclen  d_off   d_name\en");
-        for (bpos = 0; bpos < nread;) {
+        for (int bpos = 0; bpos < nread;) {
             d = (struct linux_dirent *) (buf + bpos);
             printf("%8ld  ", d\->d_ino);
             d_type = *(buf + bpos + d\->d_reclen \- 1);

man2/mprotect.2

@@ -334,7 +334,6 @@ handler(int sig, siginfo_t *si, void *unused)
 int
 main(int argc, char *argv[])
 {
-    char *p;
     int pagesize;
     struct sigaction sa;
 
@@ -361,7 +360,7 @@ main(int argc, char *argv[])
                 PROT_READ) == \-1)
         handle_error("mprotect");
 
-    for (p = buffer ; ; )
+    for (char *p = buffer ; ; )
         *(p++) = \(aqa\(aq;
 
     printf("Loop completed\en");     /* Should never happen */

man2/open_by_handle_at.2

@@ -555,7 +555,7 @@ int
 main(int argc, char *argv[])
 {
     struct file_handle *fhp;
-    int mount_id, fhsize, flags, dirfd, j;
+    int mount_id, fhsize, flags, dirfd;
     char *pathname;
 
     if (argc != 2) {
@@ -601,7 +601,7 @@ main(int argc, char *argv[])
 
     printf("%d\en", mount_id);
     printf("%d %d   ", fhp\->handle_bytes, fhp\->handle_type);
-    for (j = 0; j < fhp\->handle_bytes; j++)
+    for (int j = 0; j < fhp\->handle_bytes; j++)
         printf(" %02x", fhp\->f_handle[j]);
     printf("\en");
 
@@ -677,7 +677,7 @@ int
 main(int argc, char *argv[])
 {
     struct file_handle *fhp;
-    int mount_id, fd, mount_fd, handle_bytes, j;
+    int mount_id, fd, mount_fd, handle_bytes;
     ssize_t nread;
     char buf[1000];
 #define LINE_SIZE 100
@@ -715,7 +715,7 @@ main(int argc, char *argv[])
 
     fhp\->handle_type = strtoul(nextp, &nextp, 0);
 
-    for (j = 0; j < fhp\->handle_bytes; j++)
+    for (int j = 0; j < fhp\->handle_bytes; j++)
         fhp\->f_handle[j] = strtoul(nextp, &nextp, 16);
 
     /* Obtain file descriptor for mount point, either by opening

man2/recvmmsg.2

@@ -237,7 +237,7 @@ main(void)
 #define VLEN 10
 #define BUFSIZE 200
 #define TIMEOUT 1
-    int sockfd, retval, i;
+    int sockfd, retval;
     struct sockaddr_in addr;
     struct mmsghdr msgs[VLEN];
     struct iovec iovecs[VLEN];
@@ -259,7 +259,7 @@ main(void)
     }
 
     memset(msgs, 0, sizeof(msgs));
-    for (i = 0; i < VLEN; i++) {
+    for (int i = 0; i < VLEN; i++) {
         iovecs[i].iov_base         = bufs[i];
         iovecs[i].iov_len          = BUFSIZE;
         msgs[i].msg_hdr.msg_iov    = &iovecs[i];
@@ -276,7 +276,7 @@ main(void)
     }
 
     printf("%d messages received\en", retval);
-    for (i = 0; i < retval; i++) {
+    for (int i = 0; i < retval; i++) {
         bufs[i][msgs[i].msg_len] = 0;
         printf("%d %s", i+1, bufs[i]);
     }

man2/sched_setaffinity.2

@@ -370,7 +370,7 @@ main(int argc, char *argv[])
 {
     cpu_set_t set;
     int parentCPU, childCPU;
-    int nloops, j;
+    int nloops;
 
     if (argc != 4) {
         fprintf(stderr, "Usage: %s parent\-cpu child\-cpu num\-loops\en",
@@ -394,7 +394,7 @@ main(int argc, char *argv[])
         if (sched_setaffinity(getpid(), sizeof(set), &set) == \-1)
             errExit("sched_setaffinity");
 
-        for (j = 0; j < nloops; j++)
+        for (int j = 0; j < nloops; j++)
             getppid();
 
         exit(EXIT_SUCCESS);
@@ -405,7 +405,7 @@ main(int argc, char *argv[])
         if (sched_setaffinity(getpid(), sizeof(set), &set) == \-1)
             errExit("sched_setaffinity");
 
-        for (j = 0; j < nloops; j++)
+        for (int j = 0; j < nloops; j++)
             getppid();
 
         wait(NULL);     /* Wait for child to terminate */

man3/CPU_SET.3

@@ -329,7 +329,7 @@ main(int argc, char *argv[])
 {
     cpu_set_t *cpusetp;
     size_t size;
-    int num_cpus, cpu;
+    int num_cpus;
 
     if (argc < 2) {
         fprintf(stderr, "Usage: %s <num\-cpus>\en", argv[0]);
@@ -347,7 +347,7 @@ main(int argc, char *argv[])
     size = CPU_ALLOC_SIZE(num_cpus);
 
     CPU_ZERO_S(size, cpusetp);
-    for (cpu = 0; cpu < num_cpus; cpu += 2)
+    for (int cpu = 0; cpu < num_cpus; cpu += 2)
         CPU_SET_S(cpu, size, cpusetp);
 
     printf("CPU_COUNT() of set:    %d\en", CPU_COUNT_S(size, cpusetp));

man3/backtrace.3

@@ -232,7 +232,7 @@ backtrace() returned 8 addresses
 void
 myfunc3(void)
 {
-    int j, nptrs;
+    int nptrs;
     void *buffer[BT_BUF_SIZE];
     char **strings;
 
@@ -248,7 +248,7 @@ myfunc3(void)
         exit(EXIT_FAILURE);
     }
 
-    for (j = 0; j < nptrs; j++)
+    for (int j = 0; j < nptrs; j++)
         printf("%s\en", strings[j]);
 
     free(strings);

man3/bsearch.3

@@ -122,10 +122,8 @@ compmi(const void *m1, const void *m2)
 int
 main(int argc, char **argv)
 {
-    int i;
-
     qsort(months, nr_of_months, sizeof(months[0]), compmi);
-    for (i = 1; i < argc; i++) {
+    for (int i = 1; i < argc; i++) {
         struct mi key, *res;
         key.name = argv[i];
         res = bsearch(&key, months, nr_of_months,

man3/dl_iterate_phdr.3

@@ -307,12 +307,12 @@ static int
 callback(struct dl_phdr_info *info, size_t size, void *data)
 {
     char *type;
-    int p_type, j;
+    int p_type;
 
     printf("Name: \e"%s\e" (%d segments)\en", info\->dlpi_name,
                info\->dlpi_phnum);
 
-    for (j = 0; j < info\->dlpi_phnum; j++) {
+    for (int j = 0; j < info\->dlpi_phnum; j++) {
         p_type = info\->dlpi_phdr[j].p_type;
         type =  (p_type == PT_LOAD) ? "PT_LOAD" :
                 (p_type == PT_DYNAMIC) ? "PT_DYNAMIC" :

man3/dlinfo.3

@@ -271,7 +271,6 @@ main(int argc, char *argv[])
     void *handle;
     Dl_serinfo serinfo;
     Dl_serinfo *sip;
-    int j;
 
     if (argc != 2) {
         fprintf(stderr, "Usage: %s <libpath>\en", argv[0]);
@@ -317,7 +316,7 @@ main(int argc, char *argv[])
         exit(EXIT_FAILURE);
     }
 
-    for (j = 0; j < serinfo.dls_cnt; j++)
+    for (int j = 0; j < serinfo.dls_cnt; j++)
         printf("dls_serpath[%d].dls_name = %s\en",
                 j, sip\->dls_serpath[j].dls_name);
 

man3/duplocale.3

@@ -148,7 +148,6 @@ int
 main(int argc, char *argv[])
 {
     locale_t loc, nloc;
-    char *p;
 
     if (argc != 2) {
         fprintf(stderr, "Usage: %s string\en", argv[0]);
@@ -167,7 +166,7 @@ main(int argc, char *argv[])
     if (nloc == (locale_t) 0)
         errExit("duplocale");
 
-    for (p = argv[1]; *p; p++)
+    for (char *p = argv[1]; *p; p++)
         putchar(toupper_l(*p, nloc));
 
     printf("\en");

man3/encrypt.3

@@ -178,14 +178,13 @@ main(void)
     char orig[9] = "eggplant";
     char buf[64];
     char txt[9];
-    int i, j;
 
-    for (i = 0; i < 64; i++) {
+    for (int i = 0; i < 64; i++) {
         key[i] = rand() & 1;
     }
 
-    for (i = 0; i < 8; i++) {
+    for (int i = 0; i < 8; i++) {
-        for (j = 0; j < 8; j++) {
+        for (int j = 0; j < 8; j++) {
             buf[i * 8 + j] = orig[i] >> j & 1;
         }
         setkey(key);
@@ -193,8 +192,8 @@ main(void)
     printf("Before encrypting: %s\en", orig);
 
     encrypt(buf, 0);
-    for (i = 0; i < 8; i++) {
+    for (int i = 0; i < 8; i++) {
-        for (j = 0, txt[i] = \(aq\e0\(aq; j < 8; j++) {
+        for (int j = 0, txt[i] = \(aq\e0\(aq; j < 8; j++) {
             txt[i] |= buf[i * 8 + j] << j;
         }
         txt[8] = \(aq\e0\(aq;
@@ -202,8 +201,8 @@ main(void)
     printf("After encrypting:  %s\en", txt);
 
     encrypt(buf, 1);
-    for (i = 0; i < 8; i++) {
+    for (int i = 0; i < 8; i++) {
-        for (j = 0, txt[i] = \(aq\e0\(aq; j < 8; j++) {
+        for (int j = 0, txt[i] = \(aq\e0\(aq; j < 8; j++) {
             txt[i] |= buf[i * 8 + j] << j;
         }
         txt[8] = \(aq\e0\(aq;

man3/envz_add.3

@@ -147,10 +147,10 @@ Handle with care.
 int
 main(int argc, char *argv[], char *envp[])
 {
-    int i, e_len = 0;
+    int e_len = 0;
     char *str;
 
-    for (i = 0; envp[i] != NULL; i++)
+    for (int i = 0; envp[i] != NULL; i++)
         e_len += strlen(envp[i]) + 1;
 
     str = envz_entry(*envp, e_len, "HOME");

man3/fopencookie.3

@@ -393,8 +393,6 @@ main(int argc, char *argv[])
     FILE *stream;
     struct memfile_cookie mycookie;
     ssize_t nread;
-    long p;
-    int j;
     char buf[1000];
 
     /* Set up the cookie before calling fopencookie() */
@@ -417,7 +415,7 @@ main(int argc, char *argv[])
 
     /* Write command\-line arguments to our file */
 
-    for (j = 1; j < argc; j++)
+    for (int j = 1; j < argc; j++)
         if (fputs(argv[j], stream) == EOF) {
             perror("fputs");
             exit(EXIT_FAILURE);
@@ -425,7 +423,7 @@ main(int argc, char *argv[])
 
     /* Read two bytes out of every five, until EOF */
 
-    for (p = 0; ; p += 5) {
+    for (long p = 0; ; p += 5) {
         if (fseek(stream, p, SEEK_SET) == \-1) {
             perror("fseek");
             exit(EXIT_FAILURE);

man3/getaddrinfo.3

@@ -763,7 +763,7 @@ main(int argc, char *argv[])
 {
     struct addrinfo hints;
     struct addrinfo *result, *rp;
-    int sfd, s, j;
+    int sfd, s;
     size_t len;
     ssize_t nread;
     char buf[BUF_SIZE];
@@ -814,7 +814,7 @@ main(int argc, char *argv[])
     /* Send remaining command\-line arguments as separate
        datagrams, and read responses from server */
 
-    for (j = 3; j < argc; j++) {
+    for (int j = 3; j < argc; j++) {
         len = strlen(argv[j]) + 1;
                 /* +1 for terminating null byte */
 

man3/getaddrinfo_a.3

@@ -359,7 +359,7 @@ Here is the program source code
 int
 main(int argc, char *argv[])
 {
-    int i, ret;
+    int ret;
     struct gaicb *reqs[argc \- 1];
     char host[NI_MAXHOST];
     struct addrinfo *res;
@@ -369,7 +369,7 @@ main(int argc, char *argv[])
         exit(EXIT_FAILURE);
     }
 
-    for (i = 0; i < argc \- 1; i++) {
+    for (int i = 0; i < argc \- 1; i++) {
         reqs[i] = malloc(sizeof(*reqs[0]));
         if (reqs[i] == NULL) {
             perror("malloc");
@@ -386,7 +386,7 @@ main(int argc, char *argv[])
         exit(EXIT_FAILURE);
     }
 
-    for (i = 0; i < argc \- 1; i++) {
+    for (int i = 0; i < argc \- 1; i++) {
         printf("%s: ", reqs[i]\->ar_name);
         ret = gai_error(reqs[i]);
         if (ret == 0) {

man3/getdate.3

@@ -290,9 +290,8 @@ int
 main(int argc, char *argv[])
 {
     struct tm *tmp;
-    int j;
 
-    for (j = 1; j < argc; j++) {
+    for (int j = 1; j < argc; j++) {
         tmp = getdate(argv[j]);
 
         if (tmp == NULL) {

man3/getgrent_r.3

@@ -190,10 +190,10 @@ main(void)
         if (i)
             break;
         printf("%s (%d):", grpp\->gr_name, grpp\->gr_gid);
-        for (i = 0; ; i++) {
+        for (int j = 0; ; j++) {
-            if (grpp\->gr_mem[i] == NULL)
+            if (grpp\->gr_mem[j] == NULL)
                 break;
-            printf(" %s", grpp\->gr_mem[i]);
+            printf(" %s", grpp\->gr_mem[j]);
         }
         printf("\en");
     }

man3/getgrouplist.3

@@ -152,7 +152,7 @@ ngroups = 3
 int
 main(int argc, char *argv[])
 {
-    int j, ngroups;
+    int ngroups;
     struct passwd *pw;
     struct group *gr;
 
@@ -188,7 +188,7 @@ main(int argc, char *argv[])
     /* Display list of retrieved groups, along with group names */
 
     fprintf(stderr, "ngroups = %d\en", ngroups);
-    for (j = 0; j < ngroups; j++) {
+    for (int j = 0; j < ngroups; j++) {
         printf("%d", groups[j]);
         gr = getgrgid(groups[j]);
         if (gr != NULL)

man3/getifaddrs.3

@@ -263,7 +263,7 @@ wlp3s0   AF_INET6 (10)
 
 int main(int argc, char *argv[])
 {
-    struct ifaddrs *ifaddr, *ifa;
+    struct ifaddrs *ifaddr;
     int family, s;
     char host[NI_MAXHOST];
 
@@ -275,7 +275,8 @@ int main(int argc, char *argv[])
     /* Walk through linked list, maintaining head pointer so we
        can free list later */
 
-    for (ifa = ifaddr; ifa != NULL; ifa = ifa\->ifa_next) {
+    for (struct ifaddrs *ifa = ifaddr; ifa != NULL;
+             ifa = ifa\->ifa_next) {
         if (ifa\->ifa_addr == NULL)
             continue;
 

man3/getprotoent_r.3

@@ -197,7 +197,6 @@ main(int argc, char *argv[])
     struct protoent result_buf;
     struct protoent *result;
     char buf[MAX_BUF];
-    char **p;
 
     if (argc < 2) {
         printf("Usage: %s proto\-name [buflen]\en", argv[0]);
@@ -245,7 +244,7 @@ main(int argc, char *argv[])
 
     printf("p_name=%s; p_proto=%d; aliases=",
                 result_buf.p_name, result_buf.p_proto);
-    for (p = result_buf.p_aliases; *p != NULL; p++)
+    for (char **p = result_buf.p_aliases; *p != NULL; p++)
         printf("%s ", *p);
     printf("\en");
 

man3/getservent_r.3

@@ -195,7 +195,6 @@ main(int argc, char *argv[])
     struct servent *result;
     char buf[MAX_BUF];
     char *protop;
-    char **p;
 
     if (argc < 3) {
         printf("Usage: %s port\-num proto\-name [buflen]\en", argv[0]);
@@ -248,7 +247,7 @@ main(int argc, char *argv[])
     printf("s_name=%s; s_proto=%s; s_port=%d; aliases=",
                 result_buf.s_name, result_buf.s_proto,
                 ntohs(result_buf.s_port));
-    for (p = result_buf.s_aliases; *p != NULL; p++)
+    for (char **p = result_buf.s_aliases; *p != NULL; p++)
         printf("%s ", *p);
     printf("\en");
 

man3/hsearch.3

@@ -316,11 +316,10 @@ int
 main(void)
 {
     ENTRY e, *ep;
-    int i;
 
     hcreate(30);
 
-    for (i = 0; i < 24; i++) {
+    for (int i = 0; i < 24; i++) {
         e.key = data[i];
         /* data is just an integer, instead of a
            pointer to something */
@@ -333,7 +332,7 @@ main(void)
         }
     }
 
-    for (i = 22; i < 26; i++) {
+    for (int i = 22; i < 26; i++) {
         /* print two entries from the table, and
            show that two are not in the table */
         e.key = data[i];

man3/mallinfo.3

@@ -263,7 +263,7 @@ main(int argc, char *argv[])
 {
 #define MAX_ALLOCS 2000000
     char *alloc[MAX_ALLOCS];
-    int numBlocks, j, freeBegin, freeEnd, freeStep;
+    int numBlocks, freeBegin, freeEnd, freeStep;
     size_t blockSize;
 
     if (argc < 3 || strcmp(argv[1], "\-\-help") == 0) {
@@ -281,7 +281,7 @@ main(int argc, char *argv[])
     printf("============== Before allocating blocks ==============\en");
     display_mallinfo();
 
-    for (j = 0; j < numBlocks; j++) {
+    for (int j = 0; j < numBlocks; j++) {
         if (numBlocks >= MAX_ALLOCS) {
             fprintf(stderr, "Too many allocations\en");
             exit(EXIT_FAILURE);
@@ -297,7 +297,7 @@ main(int argc, char *argv[])
     printf("\en============== After allocating blocks ==============\en");
     display_mallinfo();
 
-    for (j = freeBegin; j < freeEnd; j += freeStep)
+    for (int j = freeBegin; j < freeEnd; j += freeStep)
         free(alloc[j]);
 
     printf("\en============== After freeing blocks ==============\en");

man3/malloc_info.3

@@ -194,13 +194,12 @@ static int numThreads, numBlocks;
 static void *
 thread_func(void *arg)
 {
-    int j;
     int tn = (int) arg;
 
     /* The multiplier \(aq(2 + tn)\(aq ensures that each thread (including
        the main thread) allocates a different amount of memory */
 
-    for (j = 0; j < numBlocks; j++)
+    for (int j = 0; j < numBlocks; j++)
         if (malloc(blockSize * (2 + tn)) == NULL)
             errExit("malloc\-thread");
 
@@ -211,7 +210,7 @@ thread_func(void *arg)
 int
 main(int argc, char *argv[])
 {
-    int j, tn, sleepTime;
+    int sleepTime;
 
     if (argc < 4) {
         fprintf(stderr,
@@ -234,7 +233,7 @@ main(int argc, char *argv[])
 
     /* Create threads that allocate different amounts of memory */
 
-    for (tn = 0; tn < numThreads; tn++) {
+    for (int tn = 0; tn < numThreads; tn++) {
         errno = pthread_create(&thr[tn], NULL, thread_func,
                                (void *) tn);
         if (errno != 0)
@@ -251,7 +250,7 @@ main(int argc, char *argv[])
 
     /* The main thread also allocates some memory */
 
-    for (j = 0; j < numBlocks; j++)
+    for (int j = 0; j < numBlocks; j++)
         if (malloc(blockSize) == NULL)
             errExit("malloc");
 

man3/mbstowcs.3

@@ -154,7 +154,6 @@ main(int argc, char *argv[])
 {
     size_t mbslen;      /* Number of multibyte characters in source */
     wchar_t *wcs;       /* Pointer to converted wide character string */
-    wchar_t *wp;
 
     if (argc < 3) {
         fprintf(stderr, "Usage: %s <locale> <string>\en", argv[0]);
@@ -206,7 +205,7 @@ main(int argc, char *argv[])
     /* Now do some inspection of the classes of the characters in
        the wide character string */
 
-    for (wp = wcs; *wp != 0; wp++) {
+    for (wchar_t *wp = wcs; *wp != 0; wp++) {
         printf("    %lc ", (wint_t) *wp);
 
         if (!iswalpha(*wp))

man3/mtrace.3

@@ -145,11 +145,9 @@ The demonstration uses the following program:
 int
 main(int argc, char *argv[])
 {
-    int j;
-
     mtrace();
 
-    for (j = 0; j < 2; j++)
+    for (int j = 0; j < 2; j++)
         malloc(100);            /* Never freed\-\-a memory leak */
 
     calloc(16, 16);             /* Never freed\-\-a memory leak */

man3/pthread_create.3

@@ -305,7 +305,7 @@ static void *
 thread_start(void *arg)
 {
     struct thread_info *tinfo = arg;
-    char *uargv, *p;
+    char *uargv;
 
     printf("Thread %d: top of stack near %p; argv_string=%s\en",
             tinfo\->thread_num, &p, tinfo\->argv_string);
@@ -314,7 +314,7 @@ thread_start(void *arg)
     if (uargv == NULL)
         handle_error("strdup");
 
-    for (p = uargv; *p != \(aq\e0\(aq; p++)
+    for (char *p = uargv; *p != \(aq\e0\(aq; p++)
         *p = toupper(*p);
 
     return uargv;
@@ -323,7 +323,7 @@ thread_start(void *arg)
 int
 main(int argc, char *argv[])
 {
-    int s, tnum, opt, num_threads;
+    int s, opt, num_threads;
     pthread_attr_t attr;
     int stack_size;
     void *res;
@@ -366,7 +366,7 @@ main(int argc, char *argv[])
 
     /* Create one thread for each command\-line argument */
 
-    for (tnum = 0; tnum < num_threads; tnum++) {
+    for (int tnum = 0; tnum < num_threads; tnum++) {
         tinfo[tnum].thread_num = tnum + 1;
         tinfo[tnum].argv_string = argv[optind + tnum];
 
@@ -388,7 +388,7 @@ main(int argc, char *argv[])
 
     /* Now join with each thread, and display its returned value */
 
-    for (tnum = 0; tnum < num_threads; tnum++) {
+    for (int tnum = 0; tnum < num_threads; tnum++) {
         s = pthread_join(tinfo[tnum].thread_id, &res);
         if (s != 0)
             handle_error_en(s, "pthread_join");

man3/pthread_getcpuclockid.3

@@ -151,7 +151,7 @@ main(int argc, char *argv[])
 {
     pthread_t thread;
     clockid_t cid;
-    int j, s;
+    int s;
 
     s = pthread_create(&thread, NULL, thread_start, NULL);
     if (s != 0)
@@ -161,7 +161,7 @@ main(int argc, char *argv[])
     sleep(1);
 
     printf("Main thread consuming some CPU time...\en");
-    for (j = 0; j < 2000000; j++)
+    for (int j = 0; j < 2000000; j++)
         getppid();
 
     pclock("Process total CPU time: ", CLOCK_PROCESS_CPUTIME_ID);

man3/pthread_setaffinity_np.3

@@ -182,7 +182,7 @@ to check the resulting CPU affinity mask of the thread.
 int
 main(int argc, char *argv[])
 {
-    int s, j;
+    int s;
     cpu_set_t cpuset;
     pthread_t thread;
 
@@ -191,7 +191,7 @@ main(int argc, char *argv[])
     /* Set affinity mask to include CPUs 0 to 7 */
 
     CPU_ZERO(&cpuset);
-    for (j = 0; j < 8; j++)
+    for (int j = 0; j < 8; j++)
         CPU_SET(j, &cpuset);
 
     s = pthread_setaffinity_np(thread, sizeof(cpuset), &cpuset);
@@ -205,7 +205,7 @@ main(int argc, char *argv[])
         handle_error_en(s, "pthread_getaffinity_np");
 
     printf("Set returned by pthread_getaffinity_np() contained:\en");
-    for (j = 0; j < CPU_SETSIZE; j++)
+    for (int j = 0; j < CPU_SETSIZE; j++)
         if (CPU_ISSET(j, &cpuset))
             printf("    CPU %d\en", j);
 

man3/qsort.3

@@ -143,8 +143,6 @@ cmpstringp(const void *p1, const void *p2)
 int
 main(int argc, char *argv[])
 {
-    int j;
-
     if (argc < 2) {
         fprintf(stderr, "Usage: %s <string>...\en", argv[0]);
         exit(EXIT_FAILURE);
@@ -152,7 +150,7 @@ main(int argc, char *argv[])
 
     qsort(&argv[1], argc \- 1, sizeof(char *), cmpstringp);
 
-    for (j = 1; j < argc; j++)
+    for (int j = 1; j < argc; j++)
         puts(argv[j]);
     exit(EXIT_SUCCESS);
 }

man3/rand.3

@@ -213,7 +213,7 @@ when given a particular seed.
 int
 main(int argc, char *argv[])
 {
-    int j, r, nloops;
+    int r, nloops;
     unsigned int seed;
 
     if (argc != 3) {
@@ -225,7 +225,7 @@ main(int argc, char *argv[])
     nloops = atoi(argv[2]);
 
     srand(seed);
-    for (j = 0; j < nloops; j++) {
+    for (int j = 0; j < nloops; j++) {
         r =  rand();
         printf("%d\en", r);
     }

man3/strcat.3

@@ -208,14 +208,13 @@ int
 main(int argc, char *argv[])
 {
 #define LIM 4000000
-    int j;
     char p[LIM + 1];    /* +1 for terminating null byte */
     time_t base;
 
     base = time(NULL);
     p[0] = \(aq\e0\(aq;
 
-    for (j = 0; j < LIM; j++) {
+    for (int j = 0; j < LIM; j++) {
         if ((j % 10000) == 0)
             printf("%d %ld\en", j, (long) (time(NULL) \- base));
         strcat(p, "a");

man3/strtok.3

@@ -250,7 +250,6 @@ main(int argc, char *argv[])
 {
     char *str1, *str2, *token, *subtoken;
     char *saveptr1, *saveptr2;
-    int j;
 
     if (argc != 4) {
         fprintf(stderr, "Usage: %s string delim subdelim\en",
@@ -258,7 +257,7 @@ main(int argc, char *argv[])
         exit(EXIT_FAILURE);
     }
 
-    for (j = 1, str1 = argv[1]; ; j++, str1 = NULL) {
+    for (int j = 1, str1 = argv[1]; ; j++, str1 = NULL) {
         token = strtok_r(str1, argv[2], &saveptr1);
         if (token == NULL)
             break;

man3/tsearch.3

@@ -322,11 +322,10 @@ action(const void *nodep, VISIT which, int depth)
 int
 main(void)
 {
-    int i;
     void *val;
 
     srand(time(NULL));
-    for (i = 0; i < 12; i++) {
+    for (int i = 0; i < 12; i++) {
         int *ptr = xmalloc(sizeof(*ptr));
         *ptr = rand() & 0xff;
         val = tsearch((void *) ptr, &root, compare);

man3/wordexp.3

@@ -234,11 +234,10 @@ main(int argc, char **argv)
 {
     wordexp_t p;
     char **w;
-    int i;
 
     wordexp("[a\-c]*.c", &p, 0);
     w = p.we_wordv;
-    for (i = 0; i < p.we_wordc; i++)
+    for (int i = 0; i < p.we_wordc; i++)
         printf("%s\en", w[i]);
     wordfree(&p);
     exit(EXIT_SUCCESS);

man5/core.5

@@ -654,7 +654,7 @@ Total bytes in core dump: 282624
 int
 main(int argc, char *argv[])
 {
-    int tot, j;
+    int tot;
     ssize_t nread;
     char buf[BUF_SIZE];
     FILE *fp;
@@ -676,7 +676,7 @@ main(int argc, char *argv[])
        pipe program */
 
     fprintf(fp, "argc=%d\en", argc);
-    for (j = 0; j < argc; j++)
+    for (int j = 0; j < argc; j++)
         fprintf(fp, "argc[%d]=<%s>\en", j, argv[j]);
 
     /* Count bytes in standard input (the core dump) */

man7/aio.7

@@ -295,7 +295,7 @@ int
 main(int argc, char *argv[])
 {
     struct sigaction sa;
-    int s, j;
+    int s;
     int numReqs;        /* Total number of queued I/O requests */
     int openReqs;       /* Number of I/O requests still in progress */
 
@@ -334,7 +334,7 @@ main(int argc, char *argv[])
     /* Open each file specified on the command line, and queue
        a read request on the resulting file descriptor */
 
-    for (j = 0; j < numReqs; j++) {
+    for (int j = 0; j < numReqs; j++) {
         ioList[j].reqNum = j;
         ioList[j].status = EINPROGRESS;
         ioList[j].aiocbp = &aiocbList[j];
@@ -377,7 +377,7 @@ main(int argc, char *argv[])
 
             printf("got SIGQUIT; canceling I/O requests: \en");
 
-            for (j = 0; j < numReqs; j++) {
+            for (int j = 0; j < numReqs; j++) {
                 if (ioList[j].status == EINPROGRESS) {
                     printf("    Request %d on descriptor %d:", j,
                             ioList[j].aiocbp\->aio_fildes);
@@ -401,7 +401,7 @@ main(int argc, char *argv[])
            in progress */
 
         printf("aio_error():\en");
-        for (j = 0; j < numReqs; j++) {
+        for (int j = 0; j < numReqs; j++) {
             if (ioList[j].status == EINPROGRESS) {
                 printf("    for request %d (descriptor %d): ",
                         j, ioList[j].aiocbp\->aio_fildes);
@@ -433,7 +433,7 @@ main(int argc, char *argv[])
     /* Check status return of all I/O requests */
 
     printf("aio_return():\en");
-    for (j = 0; j < numReqs; j++) {
+    for (int j = 0; j < numReqs; j++) {
         ssize_t s;
 
         s = aio_return(ioList[j].aiocbp);

man7/inotify.7

@@ -942,9 +942,7 @@ handle_events(int fd, int *wd, int argc, char* argv[])
     char buf[4096]
         __attribute__ ((aligned(__alignof__(struct inotify_event))));
     const struct inotify_event *event;
-    int i;
     ssize_t len;
-    char *ptr;
 
     /* Loop while events can be read from inotify file descriptor. */
 
@@ -967,7 +965,7 @@ handle_events(int fd, int *wd, int argc, char* argv[])
 
         /* Loop over all events in the buffer */
 
-        for (ptr = buf; ptr < buf + len;
+        for (char *ptr = buf; ptr < buf + len;
                 ptr += sizeof(struct inotify_event) + event\->len) {
 
             event = (const struct inotify_event *) ptr;
@@ -983,7 +981,7 @@ handle_events(int fd, int *wd, int argc, char* argv[])
 
             /* Print the name of the watched directory */
 
-            for (i = 1; i < argc; ++i) {
+            for (int i = 1; i < argc; ++i) {
                 if (wd[i] == event\->wd) {
                     printf("%s/", argv[i]);
                     break;

man7/sock_diag.7

@@ -711,13 +711,12 @@ print_diag(const struct unix_diag_msg *diag, unsigned int len)
         return \-1;
     }
 
-    struct rtattr *attr;
     unsigned int rta_len = len \- NLMSG_LENGTH(sizeof(*diag));
     unsigned int peer = 0;
     size_t path_len = 0;
     char path[sizeof(((struct sockaddr_un *) 0)\->sun_path) + 1];
 
-    for (attr = (struct rtattr *) (diag + 1);
+    for (struct rtattr *attr = (struct rtattr *) (diag + 1);
              RTA_OK(attr, rta_len); attr = RTA_NEXT(attr, rta_len)) {
         switch (attr\->rta_type) {
         case UNIX_DIAG_NAME:

man7/unix.7

@@ -1063,7 +1063,6 @@ int
 main(int argc, char *argv[])
 {
     struct sockaddr_un addr;
-    int i;
     int ret;
     int data_socket;
     char buffer[BUFFER_SIZE];
@@ -1098,7 +1097,7 @@ main(int argc, char *argv[])
 
     /* Send arguments. */
 
-    for (i = 1; i < argc; ++i) {
+    for (int i = 1; i < argc; ++i) {
         ret = write(data_socket, argv[i], strlen(argv[i]) + 1);
         if (ret == \-1) {
             perror("write");

man7/user_namespaces.7

@@ -1149,13 +1149,13 @@ usage(char *pname)
 static void
 update_map(char *mapping, char *map_file)
 {
-    int fd, j;
+    int fd;
     size_t map_len;     /* Length of \(aqmapping\(aq */
 
     /* Replace commas in mapping string with newlines */
 
     map_len = strlen(mapping);
-    for (j = 0; j < map_len; j++)
+    for (int j = 0; j < map_len; j++)
         if (mapping[j] == \(aq,\(aq)
             mapping[j] = \(aq\en\(aq;