[英]fgets() causing segmentation fault when reading file
I'm trying to use fgets() to read text from a file and I keep getting a segmentation fault. 我正在尝试使用fgets()从文件中读取文本,并且不断出现分段错误。 The program reads in the entire file and then after it reads the last line it crashes.
该程序读取整个文件,然后在读取最后一行后崩溃。 Any help would be appreciated.
任何帮助,将不胜感激。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
char *readFile(FILE *);
char *readFile(FILE *file){
int *outputSize = (int *)malloc(sizeof(int));
(*outputSize) = 1024;
char *buf = (char *)malloc(sizeof(char)*1024);
char *output = (char *)malloc(sizeof(char)*(*outputSize));
*output='\0';
while(fgets(buf,1024,file)){
if(strlen(output)+strlen(buf)+1>(*outputSize)){
printf("REALLOCATING...");
(*outputSize) *=2;
output = realloc(output,sizeof(char)*(*outputSize));
}
printf("BUFFER SIZE: %d\nBUFFER : %s\n",strlen(buf),buf);
strcat(output,buf);
printf("OUTPUT SIZE: %d\nOUTPUT: %s\n",strlen(output),output);
}
printf("FREEING...");
free(outputSize);
free(buf);
return output;
}
Your code is very hard to read, and therefore very hard to debug. 您的代码很难阅读,因此很难调试。 Which is why you're asking for help debugging it.
这就是为什么您需要帮助调试它的原因。
You don't need to read a file line-by-line when you know you're reading the whole file. 当您知道要读取整个文件时,无需逐行读取文件。 Simplify that code and just read the whole file - that makes it a lot easier to troubleshoot.
简化该代码,仅读取整个文件,这使故障排除变得更加容易。 (This code even has all error checking in less lines, and IMO is a LOT easier to understand, even without comments or debug statements that tell you what's going on)
(此代码甚至可以在更少的行中进行所有错误检查,并且即使没有注释或调试语句来告诉您发生了什么,IMO还是很容易理解的)
char *readFile( FILE *file )
{
struct stat sb;
if ( !fstat( fileno( file ), &sb ) )
{
return( NULL );
}
if ( -1 == fseek( file, 0, SEEK_SET ) )
{
return( NULL );
}
char *data = malloc( sb.st_size + 1 );
if ( data == NULL )
{
return( NULL );
}
/* this error check might not work in text mode because
of \r\n translation */
size_t bytesRead = fread( data, 1, sb.st_size, file );
if ( bytesRead != sb.st_size )
{
free( data );
return( NULL );
}
data[ sb.st_size ] = '\0';
return( data );
}
Header files will need to be updated. 头文件将需要更新。
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