strerror.c

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 Copyright (c) 2021 Walt Elam
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/***************************************************************************//**
 @file strerror.c
 
 @brief Defines the strerror function
*******************************************************************************/
#include <errno.h>
#include <string.h>
 
/*******************************************************************************
 strerror
*//**
 @brief Maps an error number to an error message string
 @param errnum Error number being mapped
 
 The strerror function maps the error number in errnum to an error message
 string.
 
 The implementation shall behave as if no library function calls the strerror
 function.
 
 @return A pointer to a string representation of the error number
*******************************************************************************/
char *
strerror(int errnum)
{
 char *str = NULL;
 
 switch (errnum)
 {
 case EDOM:
 str = "EDOM - An input argument is outside the domain over which the mathematical function is defined";
 break;
 
 case ERANGE:
 str = "ERANGE - The result of the function cannot be represented as a double value";
 break;
 
 default:
 str = "E??? - Unknown error number";
 break;
 }
 
 return str;
}