threads/strerror.c

This is threads/strerror.c (Listing 31-1, page 664), an example from the book, The Linux Programming Interface.

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Cover of The Linux Programming Interface

+/* strerror.c
+
+   An implementation of strerror() that is not thread-safe.
+*/
 #define _GNU_SOURCE                 /* Get '_sys_nerr' and '_sys_errlist'
                                        declarations from <stdio.h> */
 #include <stdio.h>
 #include <string.h>                 /* Get declaration of strerror() */
 
 #define MAX_ERROR_LEN 256           /* Maximum length of string
                                        returned by strerror() */
 
 static char buf[MAX_ERROR_LEN];     /* Statically allocated return buffer */
 
 char *
 strerror(int err)
 {
     if (err < 0 || err >= _sys_nerr || _sys_errlist[err] == NULL) {
         snprintf(buf, MAX_ERROR_LEN, "Unknown error %d", err);
     } else {
         strncpy(buf, _sys_errlist[err], MAX_ERROR_LEN - 1);
         buf[MAX_ERROR_LEN - 1] = '\0';          /* Ensure null termination */
     }
 
     return buf;
 }

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