c - Check if file exists, including on PATH -

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given filename in c, want determine whether file exists , has execute permission on it. i've got is:

if( access( filename, x_ok) != 0 ) {

but wont search path files , match directories (which don't want). please help?

edit:

as alternative, seeing i'm running execvp() in child process, there way check return value of execvp() , signal parent process die error message?

this code's not quite want, blindly executes first thing comes to. can modify search code instead of calling execve call access , stat find out if it's not directory. think last function, execvepath, has replaced.

in best unix tradition, code "self-documenting" (i.e., undocumented).

#include <string.h> #include <stdlib.h> #include <unistd.h> #include <stdio.h>  #include "shellpath.h"  static void *malloc_check(const char *what, size_t n) {   void *p = malloc(n);   if (p == null) {     fprintf(stderr, "cannot allocate %zu bytes %s\n", n, what);     exit(2);   }   return p; }  static char *strsave(const char *s, const char *lim) {   if (lim == null)     lim = s + strlen(s);   char *p = malloc_check("save string", lim - s + 1);   strncpy(p, s, lim-s);   p[lim-s] = '\0';   return p; }  char ** shellpath(void) {   const char *path = getenv("path");   if (!path)     path = "/bin:/usr/bin:/usr/local/bin";    char **vector = // size overkill     malloc_check("hold path elements", strlen(path) * sizeof(*vector));    const char *p = path;   int next = 0;   while (p) {     char *q = strchr(p, ':');     vector[next++] = strsave(p, q);     p = q ? q + 1 : null;   }   vector[next] = null;   return vector; }  void freeshellpath (char *shellpath[]) {   (int = 0; shellpath[i]; i++)     free(shellpath[i]);   free(shellpath); } unsigned maxpathlen(char *path[], const char *base) {   unsigned blen = strlen(base);   unsigned n = 0;   (int = 0; path[i]; i++) {     unsigned pn = strlen(path[i]);     if (pn > n) n = pn;   }   return blen+n+1; }    void execvepath(char *path[], const char *base, char *const argv[],                 char *const envp[]) {   if (strchr(base, '/'))     execve(base, argv, envp);   else {     size_t maxlen = maxpathlen(path, base)+1;     char *buf = malloc_check("hold path", maxlen);     (int = 0; path[i]; i++) {       snprintf(buf, maxlen, "%s/%s", path[i], base);       execve(buf, argv, envp);     }   } }

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