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.
Syntax:
void perror(const char *str)
Parameters:
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;
}
Output:
Can not open the said file.: No such file or directory
C Programming Code Editor:
Previous C Programming: C puts()
C Programming: Tips of the Day
Reading a string with scanf :
An array "decays" into a pointer to its first element, so scanf("%s", string) is equivalent to scanf("%s", &string[0]). On the other hand, scanf("%s", &string) passes a pointer-to-char[256], but it points to the same place.
Then scanf, when processing the tail of its argument list, will try to pull out a char *. That's the Right Thing when you've passed in string or &string[0], but when you've passed in &string you're depending on something that the language standard doesn't guarantee, namely that the pointers &string and &string[0] -- pointers to objects of different types and sizes that start at the same place -- are represented the same way.
Ref : https://bit.ly/3pdEk6f
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