Thread: errno

How can i get the number of errno to pass to a function?

I know they are global variable, but i need to control an array with the value passed by errno. But, they not works. Here is the code:

Code:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>

const char *descricao[] = {"Operação não permitida", "Arquivo ou diretório inexistente"};

const char *abrir_arquivo(char *arquivo)
{
	FILE *fp;
	if ((fp = fopen(arquivo, "r")) == NULL)
		return descricao[errno];
	else
                return "Ok";
}

int main (void)
{
	printf("%s\n", abrir_arquivo("asdasdasd"));
	return 1;
}

This code returns this following error message:
Segmentation fault (core dumped)

Its probably the errno is greater than 1, then the error is displayed.

This follows worked perfectly, but has much work (I need to do this in 92 messages) and the code is not professional:

Code:

char *erro(int erro)
{

	switch(erro)
	{
		case 1:
			return "Operação não permitida";
                        break;
		case 2:
			return "Arquivo ou diretório inexistente";
                        break;
	}
	
}

const char *abrir_arquivo(char *arquivo)
{
	FILE *fp;
	if ((fp = fopen(arquivo, "r")) == NULL)
		return erro(errno);
	else
                return "Ok";
}

int main (void)
{
	printf("%s\n", abrir_arquivo("asdasdasd"));
	return 1;
}

My question is:
How can I pass the correct number of errno to my function, so that this error is not more show?

Eh? Why not just call strerror()? The whole purpose of strerror() is to convert errno values to strings. It uses the locale, so it should display in the correct language. As a bonus, your error messages will work in other languages as well.

Originally Posted by Dave_Sinkula

Or just perror?

Sure, if all you're going to do is display the message anyway, just call perror().

I do not want to call strerror nor perror because I must translate the error messages to Portuguese.

Do you know any way to translate them?

Thanks for the help.

How can I access the locale to translate then?

Thanks and sorry for my bad reply...

I know english and portuguese. Im from Brazil.

Originally Posted by galindro

How can I access the locale to translate then?

Thanks and sorry for my bad reply...

The locale is supposed to be set automatically. If you are running a Portuguese version of Windows, then perror() should automatically show error messages in Portuguese. If you're running some form of UNIX, then you just need to make sure your locale is configured properly. How you do it is OS-dependent.

Point begin, you don't have to do anything in the code to make it happen.

matsp, thank you for the help.

The errno messages of FreeBSD, returns number between 1 and 92. The index of arrays in C, begins with 0. Here is the error. The errno returns me the number 2, but the max value of my array is 1!!!

Here is the correct code:

Code:

const char *descricao[] = {"", "Operação não permitida", "Arquivo ou diretório inexistente"};

const char *abrir_arquivo(char *arquivo)
{
	FILE *fp;
	int *a;
	
	if ((fp = fopen(arquivo, "r")) == NULL)
	{
		if ((errno >= 0) && (errno <= 2))
			return descricao[errno];
		else
			return "Erro desconhecido";
	}		
	else
		return "Aberto";
}

int main (void)
{
	printf("%s\n", abrir_arquivo("asdasdasd"));
	return 1;
}

Thanks for all

Best Regards!

Now, I've got the same error, when I try to concat strings:

Segmentation fault (core dumped)

Here is the code:

Code:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>

#define INTSIZE 2

char *itoa(int value)
{
	int count, i, sign;
	char *ptr, *string, *temp;

	count = 0;
	if ((sign = value) < 0) 
	{ 						
		value = -value;		
		count++; 			
	}


	temp = (char *) malloc(INTSIZE + 2);
	if (temp == NULL)
	{
		return(NULL);
	}
	memset(temp,'\0', INTSIZE + 2);

	string = (char *) malloc(INTSIZE + 2);
	if (string == NULL)
	{
		return(NULL);
	}
	memset(string,'\0', INTSIZE + 2);
	ptr = string; 


	do
	{
		*temp++ = value % 10 + '0'; 
		count++;
	} while (( value /= 10) >0);

	if (sign < 0) 
		*temp++ = '-';

	*temp-- = '\0'; 

	for (i = 0; i < count; i++, temp--, ptr++)
	{
		memcpy(ptr,temp,sizeof(char));
	}

	return(string);
}

char *descricao[] = {"", "Operação não permitida", "Arquivo ou diretório inexistente"};

char *abrir_arquivo(char *arquivo)
{
	FILE *fp;
	char *erro;

  
	if ((fp = fopen(arquivo, "r")) == NULL)
	{
		if ((errno >= 0) && (errno <= 2))
		{
			strcat(descricao[errno]," - Cód.: ");
			strcat(descricao[errno],itoa(errno));
			return descricao[errno];
		}	
		else
			return "Erro desconhecido";
	}		
	else
		return "Aberto";
}

int main (void)
{
	printf("%s\n", abrir_arquivo("asdasdasd"));
	return 1;
}

Does anyone know what might be happening?