我有兩個功能。在find_host(...)
我分配了要在main
函數free
的內存。如何正確釋放C中分配的內存?
char* find_host(char* filename){
char *x = malloc(20);
sprintf(x, filename);
const char* t = "10";
int len = (int) strcspn(filename, t);
x[len] = '\0';
return ++x;
}
int main(){
char *filename = "/CERN0/out_79.MERGE";
char *word = find_host(filename);
free(word);
return 0;
}
但free(word)
給我:
*** Error in `/home/ken/.CLion2016.2/system/cmake/generated/First-6a656bbe/6a656bbe/Debug/First': free(): invalid pointer: 0x00000000008b1011 ***
======= Backtrace: =========
/lib/x86_64-linux-gnu/libc.so.6(+0x77725)[0x7f926862f725]
/lib/x86_64-linux-gnu/libc.so.6(+0x7ff4a)[0x7f9268637f4a]
/lib/x86_64-linux-gnu/libc.so.6(cfree+0x4c)[0x7f926863babc]
/home/ken/.CLion2016.2/system/cmake/generated/First-6a656bbe/6a656bbe/Debug/First[0x4006e9]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7f92685d8830]
/home/ken/.CLion2016.2/system/cmake/generated/First-6a656bbe/6a656bbe/Debug/First[0x400579]
======= Memory map: ========
如何應該正確free
內存?
你沒有返回 - 並釋放 - 由'malloc'給出的指針。你已經改變了它。你只能「釋放」你獲得的確切價值。 –
爲什麼'return ++ x'? – jxh
因爲我想返回''CERN'',而不是''/ CERN''。 –