Recent questions tagged C

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c - Since we have snprintf, why we don't have a snscanf?

I have snprintf and it can avoid a buffer overflow, but why there is no function called snscanf? Code: int ... do we have only have snprintf? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - sizeof for a null terminated const char*

const char* a; how do I make sure that string 'a' is null terminated? when a = "abcd" and I do sizeof(a), ... it were, I would have gotten 5 ? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - When main is defined without parameters, will argc and argv still be present on the stack?

Consider the very simple: int main(void) { return 0; } I compiled it (with mingw32-gcc) and executed it as ... dependant? Answer: Yes, and no. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - static inline functions in a header file

Lately I have been making an attempt to read more open source C code. A common pattern that I have been adopting ... (hash)); return hash; } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Is there a #define for C99?

I want to do something in C99 one way, otherwise to perform it another way. What is the #define to check for? #ifdef C99 ... #else ... #endif See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - error: `itoa` was not declared in this scope

I have a sample c file called itoa.cpp as below: #include <stdio.h> #include <stdlib.h> int main () { int i; ... code? How to get rid of this? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - what is the significance of pkg-config in gcc?

While building a dbus-example, I found that we need to add a pkg-config in gcc. For example: gcc `pkg-config ... extra here? what is --libshere? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Macro to turn off printf statements

What MACRO can be used to switch off printf statements, rather than removing them all for deployment builds, I ... a Panda board running Ubuntu. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Efficiently dividing unsigned value by a power of two, rounding up

I want to implement unsigneda integer division by an arbitrary power of two, rounding up, ... Y bench_c_divide_peter_64 220 Y bench_c_divide_user23_64 212 Y bench_c_divide_use...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Is malloc deterministic?

Is malloc deterministic? Say If I have a forked process, that is, a replica of another process, and at ... virtual memory, not physical one. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - what is the meaning of restrict in the function signature?

int pthread_create(pthread_t *restrict thread, const pthread_attr_t *restrict attr, void *(*start_routine)(void*), ... meaning of restrict is? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - implicit declaration of function usleep

gcc (GCC) 4.6.3 c89 I am trying to use usleep. However, I keep getting the following warning: implicit declaration ... a to do with the above? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What does #include actually do?

In C (or a language based on C), one can happily use this statement: #include "hello.h"; And voila, every ... There's gotta be more than that. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - GLib-CRITICAL **: Source ID XXX was not found when attempting to remove it

I made a treeview with a treestore as model. The window is shown as expected, but when I click in the "+" to ... ptr); return 0; } Any ideas? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Should I set errno?

I'm writing a module which exports an interface similar to send and recv. Since those functions are supposed to ... and portable for any system? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - gcc -O0 still optimizes out "unused" code. Is there a compile flag to change that?

As I brought up in this question, gcc is removing (yes, with -O0) a line of code _mm_div_ss(s1, s2 ... think everything is working as intended. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How does an array of pointers to pointers work?

char **Data[70]={NULL}; What is the correct terminology for this? How else could it be written? What does ... . Any help is appreciated. Thanks. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Finding the squares in a plane given n points

Given n points in a plane , how many squares can be formed ...?? I tried this by calculating the distances ... code to perform the above... See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How can I use PCRE to get all match groups?

I am inexperienced with using C, and I need to use PCRE to get matches. Here is a sample of my source code: ... the matches; how can I do that? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - LZW compression/decompression under low memory conditions

Can anybody give pointers how I can implement lzw compression/decompression in low memory conditions (< 2k). is that possible? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - What is the use of Static local variable when we can get a global variable at the same cost?

In C ,what is the use of static storage class when an external variable can serve its purpose at the same cost ie. ... that i m not aware of. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How to set the size of the Non-client area of a Win32 window (native)

How to set the size of the Non-client area of a Win32 window (native). What I want is to make the ... of the corresponding window client area. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How To Use Condition Variable

The Linux Programming Interface book has a piece of code (producer/consumer) to show how condition variable works: static ... use it in an if? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - How do I generate points that match a histogram?

I am working on a simulation system. I will soon have experimental data (histograms) for the real- ... have different distribution functions. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Dealing With Asynchronous Signals In Multi Threaded Program

The Linux Programming Interface Book has mentioned a method for dealing with asynchronous signals in a multi ... inside signal handler? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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552 views

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c - Memory not freed but still reachable, is it leaking?

By checking with valgrind, I see that 5 blocks of memory were not freed after terminating my program, but they are ... free(s3); return 0; } See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - Linux Kernel - why a function's address in System.map is one byte preceding its address as seen in real time?

In linux kernel source code, added this lines in tasklet_action code: printk("tasklet_action = %p " , *tasklet_action ... an one byte offset? See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c - how to use shared memory to communicate between two processes

I am trying to communicate between two processes. I am trying to save data(like name, phone number, address) ... shared_memory[3]. Thank you. See Question&Answers more detail:os...

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

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