Function Declared Implicitly Error
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C Implicit Declaration Of Function Malloc
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Implicit Function Declaration Fprintf
declaration of function Please help me understand why is it coming. c compiler-warnings share|improve this question edited Dec 9 '11 at 3:51 Andrew Marshall 63.7k12134153 asked Dec 9 '11 at 3:49 Angus 2,961195495 A "why does it not give an error version": stackoverflow.com/questions/434763/… –Ciro Santilli 烏坎事件2016六四事件 法轮功 May 13 '15 at 7:27 add a comment| 6 Answers 6 active oldest votes up vote 103 down vote accepted You are using a function for implicit declaration definition which the compiler has not seen a declaration ("prototype") yet. For example: int main() { fun(2, "21"); /* The compiler has not seen the declaration. */ return 0; } int fun(int x, char *p) { /* ... */ } You need to declare your function before main, like this, either directly or in a header: int fun(int x, char *p); share|improve this answer edited Dec 9 '11 at 3:53 answered Dec 9 '11 at 3:50 cnicutar 122k13193256 6 As an addition if you have given the prototype check that it isn't just a typo. Also if its from an external library check that you have included it. –smitec Dec 9 '11 at 3:53 14 Why is this a warning and not an error? –Flimm Nov 21 '13 at 16:15 I cannot run the code after I get this warning. So it behaves like an error. –Mien Jan 21 '14 at 13:36 @Flimm, C99 and C89/C90 has different setting for this –How Chen Jan 15 '15 at 6:06 @Flimm stackoverflow.com/questions/434763/… –Ciro Santilli 烏坎事件2016六四事件 法轮功 May 13 '15 at 7:29 add a comment| up vote 8 down vote The right way is to declare function prototype in header. Example main.h #ifndef MAIN_H #define MAIN_H int some_main(const char *name); #endif main.c #include "main.h" int main()
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Werror=implicit-function-declaration
the company Business Learn more about hiring developers or posting ads with us Stack Overflow nested extern declaration Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 implicit declaration of function strcmp million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up warning: implicit declaration of function up vote 80 down vote favorite 16 My compiler (GCC) is giving me the http://stackoverflow.com/questions/8440816/warning-implicit-declaration-of-function warning: warning: implicit declaration of function Please help me understand why is it coming. c compiler-warnings share|improve this question edited Dec 9 '11 at 3:51 Andrew Marshall 63.7k12134153 asked Dec 9 '11 at 3:49 Angus 2,961195495 A "why does it not give an error version": stackoverflow.com/questions/434763/… –Ciro Santilli 烏坎事件2016六四事件 法轮功 May 13 '15 at 7:27 add a comment| 6 Answers 6 active oldest votes up vote 103 down vote accepted http://stackoverflow.com/questions/8440816/warning-implicit-declaration-of-function You are using a function for which the compiler has not seen a declaration ("prototype") yet. For example: int main() { fun(2, "21"); /* The compiler has not seen the declaration. */ return 0; } int fun(int x, char *p) { /* ... */ } You need to declare your function before main, like this, either directly or in a header: int fun(int x, char *p); share|improve this answer edited Dec 9 '11 at 3:53 answered Dec 9 '11 at 3:50 cnicutar 122k13193256 6 As an addition if you have given the prototype check that it isn't just a typo. Also if its from an external library check that you have included it. –smitec Dec 9 '11 at 3:53 14 Why is this a warning and not an error? –Flimm Nov 21 '13 at 16:15 I cannot run the code after I get this warning. So it behaves like an error. –Mien Jan 21 '14 at 13:36 @Flimm, C99 and C89/C90 has different setting for this –How Chen Jan 15 '15 at 6:06 @Flimm stackoverflow.com/questions/434763/… –Ciro Santilli 烏坎事件2016六四事件 法轮功 May 13 '15 at 7:29 add a comment| up vote 8 down vote The right way is to declare function prototype in header. Example main.h #ifndef MAIN_H #define MAIN_
here for a quick overview of the site Help Center http://stackoverflow.com/questions/17871338/keep-getting-implicit-declaration-error Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss implicit declaration Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up keep getting implicit declaration error up vote 0 down vote favorite 1 I keep getting these errors when compiling. implicit declaration of I modified the code that runs on an arduino to run on my raspberry pi. test1.c: In function ‘loop’: test1.c:24:3: warning: implicit declaration of function ‘rotateDeg’ [-Wimplicit-function-declaration] test1.c:33:3: warning: implicit declaration of function ‘rotate’ [-Wimplicit-function-declaration] test1.c: At top level: test1.c:42:6: warning: conflicting types for ‘rotate’ [enabled by default] test1.c:33:3: note: previous implicit declaration of ‘rotate’ was here test1.c: In function ‘rotate’: test1.c:46:3: warning: implicit declaration of function ‘abs’ [-Wimplicit-function-declaration] test1.c: At top level: test1.c:61:6: warning: conflicting types for ‘rotateDeg’ [enabled by default] test1.c:24:3: note: previous implicit declaration of ‘rotateDeg’ was here /usr/lib/gcc/arm-linux-gnueabihf/4.6/../../../arm-linux-gnueabihf/crt1.o: In function `_start': (.text+0x34): undefined reference to `main' collect2: ld returned 1 exit status Here is my source code: #include