Fopen Error Handling C
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Exception Handling In C Sharp
C programming does not provide direct support for error handling but being a system programming language, it provides you access at lower level in the form of return values. Most of the C or even Unix function calls return -1 or NULL in case of any error and set an error code errno. It is set as a global variable and indicates an error occurred during any function call. You can find various error codes defined in
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C Fopen File Path
Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a error handling in c pdf minute: Sign up Error handling in file opening up vote 2 down vote favorite [Question 1] When I open a file into a function, generally I do something like this: int read_file (char *filename) { FILE *fin; if ( !(fin = https://www.tutorialspoint.com/cprogramming/c_error_handling.htm fopen(filename, "r")) ) return 1; /* ... */ return fclose(fin); } int main () { char filename[100]; if ( read_file(filename) ) { perror(filename); exit(1); } return 0; } Generally 0 return value is for errors (right?) then I can change the previous code into: int read_file (char *filename) { FILE *fin; if ( !(fin = fopen(filename, "r")) ) return 0; /* ... */ return !fclose(fin); } int main () { char filename[100]; if ( !read_file(filename) ) { perror(filename); exit(1); } return 0; } http://stackoverflow.com/questions/21267716/error-handling-in-file-opening But I think that the first code is more clean. Another option is only change return 1; into return -1; (in the first code that I wrote). What's the best version? [Question 2] If I must handle more errors, is it correct a code like this? int read_file (char *filename, int **vet) { FILE *fin; if ( !(fin = fopen(filename, "r")) ) { perror(filename); return 1; } * vet = malloc (10 * sizeof(int)); if ( *vet == NULL ) { perror("Memory allocation error.\n"); return 1; } /* ... */ return fclose(fin); } int main () { char filename[100]; int *vet; if ( read_file(filename, &vet) ) exit(1); return 0; } c file error-handling fopen fclose share|improve this question asked Jan 21 '14 at 19:52 ᴜsᴇʀ 506314 will not (fin = fopen(filename, "r") be always true? –Dipto Jan 21 '14 at 19:59 2 In general we use 0 as the default error return as 0 refers to false and non null values refers to true. But when different errors needs to be handled we use negative values for errors. In your second question it's better to return different values for different errors to be able to know exactly which error caused the fail. –rullof Jan 21 '14 at 20:02 It's more customary in C to use a negative value as error indicator and zero or a positive number for success. In your function, zero or a positive return value could i
would learn it as one of his/her initial programming assignments. This aspect of programming involves system files. Through file handling, one can perform operations like create, http://www.thegeekstuff.com/2012/07/c-file-handling modify, delete etc on system files. Here in this article I try to bring in the very basic of file handling. Hope this article will clear the top layer of this multilayer aspect. File handling functions In this article, we will cover the following functions that are popularly used in file handling : fopen() FILE *fopen(const char *path, const char *mode); The fopen() function is used to open error handling a file and associates an I/O stream with it. This function takes two arguments. The first argument is a pointer to a string containing name of the file to be opened while the second argument is the mode in which the file is to be opened. The mode can be : ‘r' : Open text file for reading. The stream is positioned at the beginning of the handling in c file. ‘r+' : Open for reading and writing. The stream is positioned at the beginning of the file. ‘w' : Truncate file to zero length or create text file for writing. The stream is positioned at the beginning of the file. ‘w+' : Open for reading and writing. The file is created if it does not exist, otherwise it is truncated. The stream is positioned at the beginning of the file. ‘a' : Open for appending (writing at end of file). The file is created if it does not exist. The stream is positioned at the end of the file. ‘a+' : Open for reading and appending (writing at end of file). The file is created if it does not exist. The initial file position for reading is at the beginning of the file, but output is always appended to the end of the file. The fopen() function returns a FILE stream pointer on success while it returns NULL in case of a failure. fread() and fwrite() size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream); size_t fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream); The functions fread/fwrite are used for reading/writing data from/to the file opened by fopen f