内存动态分配问题:main:malloc.c:3096:sYSMALLOc
我正在编写一个简单的函数来创建一个代表一副牌的列表。 下面是结构的定义内存动态分配问题:main:malloc.c:3096:sYSMALLOc,c,list,memory,malloc,valgrind,C,List,Memory,Malloc,Valgrind,我正在编写一个简单的函数来创建一个代表一副牌的列表。 下面是结构的定义 typedef struct { float valoreEff; char *seme; char *valore; } carta; struct Mazzo { carta info; struct Mazzo *nextPtr; }; typedef struct Mazzo mazzo; typedef mazzo *mazzoPtr; 下面是一个函数,它返回指向列表第一个元素的指针 mazz
typedef struct {
float valoreEff;
char *seme;
char *valore;
} carta;
struct Mazzo {
carta info;
struct Mazzo *nextPtr;
};
typedef struct Mazzo mazzo;
typedef mazzo *mazzoPtr;
下面是一个函数,它返回指向列表第一个元素的指针
mazzoPtr caricaMazzo(void){
mazzoPtr sMazzoPtr=NULL;
int val,seme;
carta buffer;
mazzoPtr newPtr;
char *tabValori[10]={"Asso","Due","Tre","Quattro","Cinque","Sei","Sette","Donna","Cavallo","Re"};
char *tabSeme[4]={"Denari","Spade","Coppe","Bastoni"};
for(seme=0;seme<4;seme++){
for(val=0;val<10;val++){
buffer.seme=tabSeme[seme];
buffer.valore=tabValori[val];
if (val<=7) {
buffer.valoreEff=val+1;
}
else {
buffer.valoreEff=0.5;
}
printf("ok\n");
newPtr=malloc(sizeof(carta));
if (newPtr==NULL){
printf("Memoria insufficiente\n");
return NULL;
}
newPtr->info=buffer;
newPtr->nextPtr=sMazzoPtr;
sMazzoPtr=newPtr;
}
}
return sMazzoPtr;
}
我也试过Valgrind,但我无法找出代码中的错误
==21848== Invalid write of size 4
==21848== at 0x8048554: caricaMazzo (in /home/gianluca/Dropbox/PROGRAMMI/progetto/main)
==21848== by 0x8048431: main (in /home/gianluca/Dropbox/PROGRAMMI/progetto/main)
==21848== Address 0x419e034 is 0 bytes after a block of size 12 alloc'd
==21848== at 0x4025BD3: malloc (vg_replace_malloc.c:236)
==21848== by 0x804851D: caricaMazzo (in /home/gianluca/Dropbox/PROGRAMMI/progetto/main)
==21848== by 0x8048431: main (in /home/gianluca/Dropbox/PROGRAMMI/progetto/main)
==21848==
我希望您能帮助我:)问题似乎出在您调用
malloc()
的线路上
newPtr
属于mazzo*
类型,但您正在为carta
分配空间,该空间太小
我认为应该是
newPtr=malloc(sizeof(mazzo))代码> 虽然这可能不是你的选择,但最好还是使用C++。在它的许多软件工程好处中,它的new
分配内存的习惯用法正好防止了这种错误,因为您必须显式使用对象类型:newPtr=newmazzo代码>作为旁白-您通常可以使用习惯用法newPtr=malloc(sizeof(*newPtr)),来防止这种类型的错误代码>-这样,指针的类型只能是正确的。稍后阅读代码的人不需要在源代码中来回跳转,以确保sizeof
操作数的类型对于指定的指针是正确的。
==21848== Invalid write of size 4
==21848== at 0x8048554: caricaMazzo (in /home/gianluca/Dropbox/PROGRAMMI/progetto/main)
==21848== by 0x8048431: main (in /home/gianluca/Dropbox/PROGRAMMI/progetto/main)
==21848== Address 0x419e034 is 0 bytes after a block of size 12 alloc'd
==21848== at 0x4025BD3: malloc (vg_replace_malloc.c:236)
==21848== by 0x804851D: caricaMazzo (in /home/gianluca/Dropbox/PROGRAMMI/progetto/main)
==21848== by 0x8048431: main (in /home/gianluca/Dropbox/PROGRAMMI/progetto/main)
==21848==