C perror() function

C library function - perror()

The perror() function is used to print an error message to stderr based on the error state stored in errno. The string pointed to by string, followed by a colon and a space, is printed to the standard error stream if string is not NULL.


void perror(const char *str)


Name Description Required /Optional
str Contains a custom message. Required

Return value

  • This function does not return any value.

Example: The following example shows the usage of perror() function.

#include <stdio.h>
#include <stdlib.h>
int main(void)
   FILE *fh;
   if ((fh = fopen("test1.txt","r")) == NULL)
      perror("Can not open the said file.");
   return 0;


Can not open the said file.: No such file or directory

C Programming Code Editor:

Previous C Programming: C puts()

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