c pointer for struct causes segment fault while doing

Question

I get a segment fault while it comes to the memset，i've looked anywhere can't know why?Can anyone tell me what's wrong?

typedef struct Ircsend1_struct{
  char type;
  char name[32];
}ircsend1_struct;

ircsend1_struct *ircpack;

char *pBuffer;
ircpack = (ircsend1_struct *)pBuffer;
memset(ircpack,0x00,sizeof(ircsend1_struct));

haccks · Accepted Answer · 2015-03-15 18:34:19Z

3

The assignment

ircpack = (ircsend1_struct *)pBuffer;

is wrong. pBuffer is uninitialized. ircpack is pointing at unknown location. Therefore, the statement

memset(ircpack,0x00,sizeof(ircsend1_struct));

will invoke undefined behavior.

answered Mar 15, 2015 at 18:34

haccks

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Comments

Iharob Al Asimi · Accepted Answer · 2015-03-15 18:33:14Z

2

Because your pointer is not initialized, maybe you mean

ircsend1_struct irpack;
char *pBuffer = &irpack;

memset(pBuffer, 0, sizeof(ircsend1_struct));

answered Mar 15, 2015 at 18:33

Iharob Al Asimi

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1 Comment

QShengyao Over a year ago

You are right.I've done what you write and problem solved.(ircsend1_struct) *ircpack is not initialized and causes segmentfault while memset.

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