1XDF_ADD_CHANNEL(3)         xdffileio library manual         XDF_ADD_CHANNEL(3)
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NAME

6       xdf_add_channel - Appends a channel to a XDF file
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SYNOPSIS

9       #include <xdfio.h>
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11       struct xdfch* xdf_add_channel(struct xdf* xdf, const char* label);
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DESCRIPTION

14       xdf_add_channel()  appends a channel to the file referenced by the han‐
15       dle xdf. The new channel is initialized with the label argument (if not
16       NULL)  and  with  the  default channel values set in the XDF file, i.e.
17       those set using channel configuration fields  in  xdf_set_conf(3)  (See
18       the related manpage).
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20       If  the  call  to  xdf_add_channel(3) is successful, the default offset
21       value (the field referenced by XDF_CF_ARROFFSET) is incremented by  the
22       size   of   the  current  default  stored  type  (field  referenced  by
23       XDF_CF_STOTYPE). As a consequence, if the channel default  values  have
24       not  changed in-between, the next call to xdf_add_channel() will create
25       a channel whose location is the array will be next to the previous one.
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27       This type of initialization allows the user  to  add  channels  without
28       having to specifically pack them: this is achieved by default.
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RETURN VALUE

31       xdf_add_channel()  returns the handle to newly created channel descrip‐
32       tor in case of success. Otherwise NULL is returned  and  errno  is  set
33       appropriately.
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ERRORS

36       EINVAL xdf is NULL.
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38       ENOMEM The system is unable to allocate resources.
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40       EPERM  the  file  referenced  by  xdf  has  been  opened  with the mode
41              XDF_READ
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SEE ALSO

44       xdf_copy_chconf(3), xdf_set_conf(3), xdf_set_chconf(3)
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50EPFL                                 2010                   XDF_ADD_CHANNEL(3)
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