我试图将结构写入文件,但在运行时遇到分段错误:
#include<stdio.h>
//just a struct for purposes of demonstration
struct my_struct{
int prop1;
int prop2;
};
//writes dummy struct to filename.dat
void writeStruct(){
FILE *file_pointer;
file_pointer = fopen("filename.dat","w");
//define and assign variables to a quick dummy struct
struct my_struct *this_struct;
this_struct->prop1=0; //seg faults here!
this_struct->prop2=1;
//write struct to file
fwrite(this_struct, sizeof(*this_struct), 1, file_pointer);
fclose(file_pointer);
}
int main(){
writeStruct();
return 0;
}
谁能帮助我了解seg错误并实现程序的目的?
您仅定义了结构的指针,没有指向任何内存。所以只是不要使用指针:
...
//define and assign variables to a quick dummy struct
struct my_struct this_struct;
this_struct.prop1=0;
this_struct.prop2=1;
//write struct to file
fwrite(&this_struct, sizeof this_struct, 1, file_pointer);
...
或由于需要使用这种方式malloc
来分配内存:
...
//define and assign variables to a quick dummy struct
struct my_struct *this_struct;
this_struct = malloc(sizeof *this_struct);
this_struct->prop1=0;
this_struct->prop2=1;
//write struct to file
fwrite(this_struct, sizeof *this_struct, 1, file_pointer);
...
不要忘记free
在指针无法到达之前进行呼叫。
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