INFO: C2059, C2065, C2143 May Be Caused by Not Including Header (65304)

SUMMARY

In Microsoft C/C++, when the compiler encounters a previously undeclared token used in a context that assumes its existence, the compiler will generate an error. For example, if a function has been prototyped to take a pointer of type FILE as a parameter and if STDIO.H has not been included previously, the compiler issues one or more errors (see the Sample Code below).

In these cases, there are several possible compiler errors that may be generated, the most likely of which being:

C2059: syntax error : 'token'

-or-

C2065: 'identifier' : undeclared identifier

-or-

C2143: syntax error : missing 'token1' before 'token2'

To eliminate these errors, declare the desired token before using it in a statement. In many cases, this means including the appropriate system header file, such as STDIO.H.

MORE INFORMATION

When using the above compilers, the following Sample Code fails compilation. To fix, uncomment the inclusion of STDIO.H.

Sample Code

/* Compile option needed: none
 */ 

//#include <stdio.h>

void test(FILE *fp);  // This line may cause errors C2143 and C2059.

void main ()
{
  FILE *fp;          // This line may cause the C2065 error.

  test(fp);

}

void test(FILE *vp)  // This line may cause errors C2143 and C2059.
{
}