# Ioapi error in m3too;

**URL:** <https://forum.cmascenter.org/t/ioapi-error-in-m3too/2341>\
**Category:** I/O API\
**Created:** [May 15, 2021, 11:46am UTC](https://forum.cmascenter.org/t/ioapi-error-in-m3too/2341 "2021-05-15T11:46:17Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Nadia](https://avatars.discourse-cdn.com/v4/letter/n/f19dbf/32.png) [@Nadia](https://forum.cmascenter.org/u/Nadia)\
**Post date:** [May 15, 2021, 11:46am UTC](https://forum.cmascenter.org/t/ioapi-error-in-m3too/2341/1 "2021-05-15T11:46:17Z")

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Hi everyone, I am trying to install ioapi. when I typed make in m3tool folder I receive an error as below:  
/home/nadia/Libraries/ioapi-3.2-20200828/Linux5\_x86\_64gfort/libnetcdff.a(nf\_varaio.o): in function `nf\_get\_vara\_int64\_’:

nf\_varaio.F90:(.text+0x5160): multiple definition of `nf\_get\_vara\_int64\_’; /home/nadia/Libraries/ioapi-3.2-20200828/Linux5\_x86\_64gfort/libioapi.a(modncfio.o):modncfio.F90:(.text+0xc1060): first defined here

collect2: error: ld returned 1 exit status

make: \*\*\* [Makefile:243: airs2m3] Error 1

can you help me to understand the problem?  
my compiler is gfortran.

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**Author:** ![cjcoats](https://avatars.discourse-cdn.com/v4/letter/c/ac8455/32.png) [@cjcoats](https://forum.cmascenter.org/u/cjcoats)\
**Post date:** [May 15, 2021, 1:41pm UTC](https://forum.cmascenter.org/t/ioapi-error-in-m3too/2341/2 "2021-05-15T13:41:42Z")

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See the I/O API build-instructions, item 8 [https://cjcoats.github.io/ioapi/AVAIL.html#build](https://cjcoats.github.io/ioapi/AVAIL.html#build):

> For I/O API-3.2 and netCDF-4: Some configurations of netCDF-4 have INTEGER\*8 (64-bit integer) support, and some do not; the I/O API tries to make it possible to use this support if it is available, but needs to include “hacks” to cover for its absence when it isn’t. You can find out if it is included in netCDF using the command
> 
> ```
> nm libnetcdff.a | grep nf_get_var_int64_
> 
> ```
> 
> If present, you need to add the definition -DIOAPI\_NCF4=1 to the make-variable ARCHFLAGS in your MAKEINCLUDE.${BIN}. Otherewise, you will get “multiply defined symbol” errors when you attempt to compile programs.

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<div class="post-metadata">

**Author:** ![Nadia](https://avatars.discourse-cdn.com/v4/letter/n/f19dbf/32.png) [@Nadia](https://forum.cmascenter.org/u/Nadia)\
**Post date:** [May 16, 2021, 10:37am UTC](https://forum.cmascenter.org/t/ioapi-error-in-m3too/2341/3 "2021-05-16T10:37:22Z")

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thank you. the problem solved