FIX: Incorrect Use of #pragma Pack Causes C1001 Errors

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View products that this article applies to.

This article was previously published under Q119873

SYMPTOMS

When compiling code that uses #pragma pack() to pop an ID that has not been pushed after successfully popping an ID that was pushed, the compilers listed above will generate:

fatal error C1001: INTERNAL COMPILER ERROR

In addition, this error will be followed by a message similar to

(compiler file 'msc1.cpp', line 902)
Please choose the Technical Support command on the Visual C++ Help menu, or open the Technical Support help file for more information

NOTE: In Microsoft Visual Studio .NET, you receive a C4160 warning instead of the error message, so you can compile and run the program.

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RESOLUTION

Pop only IDs that have been previously pushed onto the compiler's internal stack.

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STATUS

Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.

This problem was corrected in Microsoft Visual C++ .NET.

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MORE INFORMATION

The following sample code demonstrates the bug:

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Sample Code

/* packfail.c

Compile options needed: none
*/ 

#pragma pack(push, a)
#pragma pack(push, b, 4)
#pragma pack(pop, b)
#pragma pack(pop, value)

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APPLIES TO

Microsoft Visual C++ 1.0 Professional Edition
Microsoft Visual C++ 2.0 Professional Edition
Microsoft Visual C++ 4.0 Standard Edition
Microsoft Visual C++ 4.1 Subscription
Microsoft Visual C++ 4.2 Professional Edition
Microsoft Visual C++ 5.0 Standard Edition
Microsoft Visual C++ 6.0 Service Pack 5

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kbbug kbcompiler kbfix kbnoupdate KB119873

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Retired KB Content Disclaimer

This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.

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